ci: add x-access-token user to make.sh script

Codegen is failing since switching to ephemeral tokens with `fatal: could not read Password for 'https://***@github.com': No such device or address`

This is working for [elasticsearch-js](https://github.com/elastic/elasticsearch-js/blob/4b336837419c49d3faee6ac34dbf7e3f10e7df80/.github/make.sh#L179) which uses `https://x-access-token:$CLIENTS_GITHUB_TOKEN@github.com/elastic/elastic-client-generator-js.git`

(cherry picked from commit 5337e75)

Author: MattDevy

.github/make.sh

@@ -193,7 +193,7 @@ if [[ "$CMD" == "codegen" ]]; then
       --rm -v $repo:/code/elasticsearch-php \
       $product \
       /bin/bash -x -c "cd /code && mkdir codegen && \
-      git clone https://$CLIENTS_GITHUB_TOKEN@github.com/elastic/elastic-client-generator-php.git && \
+      git clone https://x-access-token:$CLIENTS_GITHUB_TOKEN@github.com/elastic/elastic-client-generator-php.git && \
       cd /code/elastic-client-generator-php && composer install && \
       bin/elasticsearch9.php $ES_VERSION $BRANCH /code/codegen config/elasticsearch9.json && \
       find /code/elasticsearch-php/src/Endpoints/ -name "*.php" -not -name AbstractEndpoint.php -exec rm {} \;